Optical correlation methods have proved to be very useful in the design of two-dimensional (2D) pattern-recognition applications (A. VanderLugt, IEEE Trans. Inf. Theory IT-10, 139 (1964); J. L. Homer and P. D. Gianino, Appl. Opt. 23, 812 (1984); D. Psaltis, E. G. Paek, and S. S. Venkatesh, Opt. Eng. 23, 698 (1984); Ph. Refrefgier, Opt. Lett. 15, 854 (1990) and J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, New York, 1996) which are incorporated herein by reference in their entirety).
Recently, there has been increasing interest in three-dimensional (3D) optical information processing because of its vast potential applications. Several methods have been proposed to extend optical correlation methods to three-dimensional object recognition. One approach consists of processing different 2D projections of both a three-dimensional scene and a three-dimensional reference object by use of conventional 2D Fourier methods (A. Pu, R. Denkewalter, and D. Psaltis, Opt. Eng. 36, 2737 (1997) which is incorporated herein by reference in its entirety).
Other methods also involve the acquisition of different 2D perspectives, but the recognition is performed by three-dimensional Fourier-transform methods (J. Rosen, Opt. Lett. 22, 964 (1997) which is incorporated herein by reference in its entirety). This approach has analogies to incoherent-light three-dimensional imaging based on spatial coherent functions (H. Arimoto, K. Yoshimori, and K. Itoh, Opt. Commun. 170, 319 (1999) which is incorporated herein by reference in its entirety). Fourier-transform profilometry has also been applied to three-dimensional shape recognition (J. J. Esteve-Taboada, D. Mas, and J. Garcia, Appl. Opt. 22, 4760 (1999) which is incorporated herein by reference in its entirety).
However, holography, seems to be a more attractive method of performing three-dimensional image recognition, since a single hologram is able to record three-dimensional information on the object, avoiding sequential recording of several 2D perspectives and maintaining the phase (H. J. Caulfield, ed., Handbook of Optical Holography (Academic, London, 1979) which is incorporated herein by reference in its entirety).